condition mean min max ZT0-3 6.75 6.75 6.75 ZT4-7 41.5 41.5 41.5 ZT8-11 49.05 49.05 49.05 ZT12-15 28.85 28.85 28.85 ZT16-19 18.05 18.05 18.05 ZT20-23 6.7 6.7 6.7